The present invention relates to a guide bar for a motor chainsaw. It comprises a circumferential guide groove for the saw chain whereby the guide groove is delimited by two side plates forming the guide bar. The side plates are approximately congruent to one another, spaced apart by a distance, and fixedly connected to one another.
Such a sandwich-type guide bar is known from U.S. Pat. No. 5,014,435. Between the two side plates an intermediate plate in the form of a spacer is provided which, together with the side plates, is fixed in its position with a potting compound such as a synthetic resin. It is possible to provide openings in the side plates as well as in the intermediate plate in order to reduce weight which openings are filled during pouring of the resin with the resin. In practice it has been demonstrated that each one of the openings in the side plates which results in a weight reduction at the same time reduces the torsional stiffness so that the handling of the guide bar is unfavorably affected. On the other hand, smaller openings result in a satisfactory torsional stiffness but also result in a greater weight of the guide bar so that the usability of the motor chainsaw is unfavorably affected.
It is therefore an object of the present invention to provide a guide bar of the aforementioned kind such that for a low weight a high torsional stiffness can be achieved.